Diagnosis of allergies has relied upon a number of techniques for introducing various biological substances to the epidermis or dermis. In a widely accepted testing method for allergies and other immunologic conditions--the skin test--various biologicals, such as aeroallergens, food allergens, and other substances are applied by abrading, cutting or puncturing the epidermal skin layer and contacting the liquid allergenic extract or the like with the exposed skin tissue. The test areas are often on the back or arm of the patient and the tests normally cause some discomfort. If the patient is allergic to a particular biological substance which is applied, histamine or a histamine substance will be released by the affected tissue resulting in redness and swelling in that area. The specific test sites are then compared to a control test site to visually determine if the patient is allergic to a particular test substance.
The skin tests may be performed one test at a time with each allergenic extract being loaded onto a scarifier or pick and applied to the skin. An example of a device for applying single tests is shown in U.S. Pat. No. 4,270,548. As it is desirable to speed up the testing process, devices for performing multiple tests simultaneously were developed. One such skin testing device that is widely used is the applicator disclosed in U.S. Pat. No. 3,556,080 to Hein which discloses a plastic applicator having an elongate handle from which extend curved connecting legs, each one of which terminates in a pressure puncture head having a cluster of sharp points. The method of using the Hein multi-headed applicator is to place the applicator upside down with the rigid handle being supported in a holder, such as described in Hein's U.S. Design Pat. No. 247,822. Each of the pressure puncture heads or picks is then individually loaded with a testing substance by the doctor or nurse. Once the puncture heads are individually loaded, the applicator is grasped by the elongate handle and then applied to the skin in a manner such that each puncture head can penetrate the surface of the skin. Using this method requires loading each puncture head individually, which is laborious and can take a considerable amount of time.
An early form of a multi-headed skin test applicator is disclosed in U.S. Pat. No. 2,522,309 to Simon. In the Simon patent, the applicator comprises test covers (handles) having needles attached thereto that are placed over a plurality of allergen containing wells in a manner to allow the needles to enter the fluid. Each well must be filled with the desired testing substance, which is laborious and time consuming. Also, any unused testing substance must be discarded so that the wells may be cleaned and sterilized prior to storage. The covers fit snugly over the wells in a sealing relationship. When the multi-headed applicator is removed from the wells with a spiral motion, the needles touch the sides of the wells to remove excess allogenic extract. The loaded multi-headed applicator is then used in the normal manner.
The desire to simplify and speed-up allergy testing procedures has led to the development of a number of other multi-headed skin test applicators. The patent to Galy, U.S. Pat. No. 4,453,926, provides a multi-headed scarifying device for simultaneously performing a plurality of skin tests. The device has a clustered group of points that are contained in a hermetically sealed envelope with the envelope containing an active liquid substance into which the cluster points are immersed. To operate the Galy device, one must individually remove each envelope tab, which is not only time consuming, but provides an opportunity for the testing substances to drip from the exposed heads while the remaining envelopes are being removed.
U.S. Pat. No. 3,289,670 to Krug, et al. describes a multi-headed device for simultaneously performing a plurality of skin tests. The device includes a structure having a flat upper surface defining a plurality of wells. The device also includes a reusable abrading unit having multiple skin abrading members. The abrading unit fits on top of the structure so that each abrading member fits into a corresponding well and is immersed in the liquid testing substance. When the tests are performed, the abrading unit is removed from the structure and applied to the patient in the normal manner. Repeated removal and replacement of the abrading unit during a series of tests, however, can result in testing substances dripping from the individual abrading members or otherwise becoming deposited on the surface of the structure and inside the adjacent wells, thus contaminating the testing substances in the wells. In the event the testing substances become contaminated, any subsequent skin tests could be inaccurate and result in an incorrect diagnosis.
The present invention overcomes the disadvantages of the prior art by providing an autoloading apparatus and skin testing system for rapidly loading a multi-headed skin testing applicator with biologicals or other testing agents, while at the same time, effectively inhibiting the cross contamination of testing agents.